Our society is one that (unfortunately) places much of its value in the material realm of the physical. States of consciousness altered from this one can be threatening to a materialistic paradigm. Now with DMT (not linking DMT and dreaming  ), the government can simply make it illegal and restrict access as best as they can/feel necessary to prevent extractions. With dreaming on the other hand, the government can't exactly step in and say, "no you can't do that," so the "next best option" is to ridicule, mock and subjugate them. Many people don't ever remember any dreams, nor do they seem to care because it's not put up on the pedestal it deserves. Dreaming is such a peculiar phenomena and because people can often detect that their subconscious is fueling it, and that they potentially can retain some amount of control over the dream, dreaming's "real factor" can often seen to be going down. In terms of using other substances for dreaming, you may want to look into calea zacatechichi.

The reason DMT won't give you fixed answers are because there are none. Fixed answers are a construct of the ego. As humans we tend to like to create stable realities (our sense for what constitutes being real) with fixed answers. We dominantly use and/or logic; something is either this way or that way, and can't be in opposite states at the same time. DMT likes to show you realities of both/and logic; things are both this way and that way; God/the void/the universe is both hot and cold, big and small, everything and nothing, the alpha and the omega, good and evil; in hyperspace, two "objects" can be in the same place at the same time. Fixed answers are indicative of analytical reductionist thought. Fixed answers are harder to arrive at when things can be both one way and not that way at the same time. You'll want to tend to suppress or dismiss one side or the other, but you should try and keep these polar opposites balanced in your mind. Fixed answers also leave little room for growth, and it seems to me that DMT can often be about growing up spiritually and learning to relinquish concepts from spiritual childhood (most adults are spiritually like children).